# How to do IC engine CFD analysis to have results wrt crank angle ?

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 January 24, 2017, 08:59 How to do IC engine CFD analysis to have results wrt crank angle ? #1 New Member   Latheesh V M Join Date: Jan 2017 Posts: 9 Rep Power: 2 Hi. i want to do a CFD simulation of flow through intake port of an IC engine. i will be doing it with morphing mesh..so if i want to have the results wrt crank angle...i.e swirl number vs crank angle what should be my physics models? is it possible to relate the crank angle to time step and morph the piston based on? Any help or information is highly appreciated. Thanks in advance

 January 24, 2017, 10:23 #2 New Member   Kevin Join Date: Oct 2012 Posts: 29 Rep Power: 7 Just create a custom unit called "CAD" with dimension "Time" and set the conversion rate such that 1 CAD is equal to the amount of time elapsed when the crankshaft rotates 1 degree (ie, 60/(RPM*360)). Then, for any results you need (table, XY plot, annotation on scene) you can select the unit "CAD" and it will do the conversion. You can also use this for setting time step (ie, 0.5 CAD or 2 CAD or whatever). latheeshvmv likes this.

January 24, 2017, 11:57
#3
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Latheesh V M
Join Date: Jan 2017
Posts: 9
Rep Power: 2
Quote:
 Originally Posted by kirrer Just create a custom unit called "CAD" with dimension "Time" and set the conversion rate such that 1 CAD is equal to the amount of time elapsed when the crankshaft rotates 1 degree (ie, 60/(RPM*360)). Then, for any results you need (table, XY plot, annotation on scene) you can select the unit "CAD" and it will do the conversion. You can also use this for setting time step (ie, 0.5 CAD or 2 CAD or whatever).

your answer solved my first part. Is it possible to define morph positions based on the custom unit ..for example, morph positions will be at position x at 1 degree of crank rotation and morph position to be at position y at 2 degree of crank rotation

my simulation is similar to this youtube video : https://youtu.be/iTG9LuFi1AE.

 January 25, 2017, 15:52 #4 New Member   Kevin Join Date: Oct 2012 Posts: 29 Rep Power: 7 I'm not too familiar with morphing, but I believe you can set morphing according to a table in time or a field function, correct? If so, you can calculate piston position in Excel and provide that table to either definition. Alternatively, you can write the equations for moving the piston directly in a field function. I'm not sure how good your mesh quality will be by morphing the entire displacement of the piston, though - so be cautious there. latheeshvmv likes this.

January 29, 2017, 07:20
#5
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Latheesh V M
Join Date: Jan 2017
Posts: 9
Rep Power: 2
Quote:
 Originally Posted by kirrer I'm not too familiar with morphing, but I believe you can set morphing according to a table in time or a field function, correct? If so, you can calculate piston position in Excel and provide that table to either definition. Alternatively, you can write the equations for moving the piston directly in a field function. I'm not sure how good your mesh quality will be by morphing the entire displacement of the piston, though - so be cautious there.
sorry for the late replay.was caught up in some works here.

Yes it is possible. There is equation for instantaneous piston position. So may be i can equate it or provide an excel file. i will try this and post the solution here.I have seen that morphing ends up in lots of errors...mesh quality is a concern.Let me try and see how it goes. Thanks u Kevin

 Tags cfd, ic engine, intake manifold, star ccm+, time step

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